Huge Overcharge

I have tried unsuccessfully to report the fact that I was charged R2914.73 on 7 Sept on a 2 year contract, instead of R79. I have reported this several times since 20 October, I have all the reference Nos., but I just don't get any reply back My wife and I are Pensioners, living on a fixed income, so this is a huge amount they withdrew from my Savings Account, without letting me know - why take out a contract if this sort of thing is allowable? I have asked a few times if I could please speak to a Supervisor, but they say they will ask a Supervisor to phone, but this does not happen. I have also requested an itemized billing, which I was informed would cost me R25.oo which I agreed to, but still nothing!! Every time I phone them, it takes about 30 minutes to answer all the questions they ask, although I give them the latest reference no., so this all boils down to a \no win situation". Please can someone help me"